Which component is described as a round disk?

• A. Outer shell
• B. Impeller
• C. Suction port assembly
• D. Vent valve

Answer: (B)

The rotating element described as a round disk is the impeller. It’s a flat circular disk with blades attached around its edge, mounted on the shaft so it spins smoothly. As it turns, fluid is drawn in at the center and hurled outward by centrifugal force, which increases the fluid’s velocity and pressure as it moves through the pump. This circular disk shape helps balance the forces and maintain even rotation, which is essential for efficient pumping. The outer shell is the surrounding housing, the suction port assembly is the intake connection, and the vent valve is used to release trapped air—none of these are round disks like the impeller.